The present invention relates to a binder resin composition to be used for the purpose of protection or ornamentation of polyolefinic resins such as polypropylene, polyethylene, ethylene-propylene copolymer and ethylene-propylene-diene copolymer. In more detail, it relates to a chlorinated polyolefin composition to be used as a binder resin for paints, primers, printing inks or adhesives, having excellent adherence to these sheets, films and moldings and excellent other physical properties together with good stability.
Because of high productivity, broad freedom of design and many advantages such as light weight, antirust and shock resistance, in recent years, plastics have been used most frequently as the materials for automotive parts, electrical parts, building materials, food packaging films, etc. In particular, because of low price and many excellent properties such as moldability, chemical resistance, heat resistance, water resistance and good electrical characteristics, the polyolefinic resin is used extensively as the industrial materials, and is one of materials that the growth of demand thereof is most expected in future. Different from synthetic resins having polarity such as polyurethane resin, polyamide resin, acrylic resin and polyester resin, however, the polyolefinic resin has a drawback of difficult painting and adhesion because of nonpolarity and crystallinity.
For the painting and adhesion of such polyolefinic resin which is difficult in adherence, low-chlorinated polyolefin having strong adherent force to polyolefinic resin has been used so far as a binder resin. For example, in Japanese Patent Publication No. Sho 46-27489, a chlorinated isotactic polypropylene chlorinated up to 20 to 40% by weight is proposed as a binder resin for printing ink of polypropylene film. In Japanese Patent Publication Nos. Sho 50-35445 and Sho 50-37688, a chlorinated propylene-ethylene copolymer chlorinated up to 20 to 40% by weight is proposed as a binder resin for printing ink or adhesive to polyolefin. Also, in Japanese unexamined Patent Publication Nos. Sho 57-36128 and Sho 59-166534, Japanese Patent Publication Nos. Sho 63-50381 and Sho 63-36624, and the like, a low-chlorinated polypropylene or low-chlorinated propylene-olefin copolymer with chlorine content of 5 to 50% that contains carboxylic acid and/or carboxylic anhydride is proposed as a primer for painting or a binder resin for coating of polyolefinic moldings.
Further, in Japanese Unexamined Patent Publication No. Hei 1-110580, a chlorinated terpolymer that contains carboxylic acid and/or carboxylic anhydride, comprising unsaturated carboxylic acid monomer, unsaturated vinyl ester monomer and ethylene, up to 3 to 50% by weight is proposed as a binder resin for adhesive of polyolefinic resin.
In general, since the low-chlorinated polyolefins as described above are chlorinated by blowing chlorine gas after dispersing or dissolving various polyolefins into water or chlorinating solvent, chlorine is introduced heterogeneously into polyolefin. Consequently, these low-chlorinated polyolefins become unstable, resulting in a drawback of accompanying dehydrochlorination upon exposure to ultraviolet rays or high temperature to deteriorate.
As the stabilizers for these low-chlorinated polyolefins, stabilizers used for poly(vinyl chloride) being a chlorine-based resin can be applied as they are. For example, they include metal soaps such as calcium stearate and lead stearate, salts of inorganic acids such as lead oxide and tribasic lead sulfate, organometallic compounds such as dibutyl tin dilaurate and dibutyl tin maleate, and epoxy compounds such as epoxidated soybean oil and glycidyl ether of glycerine (Poly(vinyl chloride)-Its Chemistry and Industry, 3rd ed. published on Jan. 25, 1966, Asakura Book-Store Co., Ltd.).
However, almost all of stabilizers added to commercial low-chlorinated polyolefins and chlorinated paraffin are epoxy compounds. Moreover, as the use of epoxy compounds is exemplified as the stabilizers of low-chlorinated polyolefins also in Japanese Patent Publication Nos. Sho 57-31756 and Sho 60-49654, Japanese Unexamined Patent Publication Nos. Hei 6-306227 and Hei 7-73362, Japanese Patent Application Nos. Hei 8-191749 and Hei 9-21070, and the like, it is the status quo that epoxy compounds are used generally for the stabilizers of low-chlorinated polyolefins. However, the epoxy compounds cannot necessarily be said to be effective as the stabilizers of chlorinated polyolefins, thus improvement in stability of these chlorinated polyolefins has been looked for.
The invention intends to provide a chlorinated polyolefin compound for paints, primers, printing inks or adhesives, more improved in adherence and other physical properties to polyolefin by improving the stability of low-chlorinated polyolefin that was insufficient until now.